#TODO ===== BEGIN SOLUTION HERE =====

    tmin = np.inf
    tempEnd = ray.eyePoint + ray.viewDirection
    tempEnd = np.append(tempEnd, [1])
    tempEye = np.array([ray.eyePoint[0], ray.eyePoint[1], ray.eyePoint[2], 1])
    tempDirection = np.array([ray.viewDirection[0], ray.viewDirection[1], ray.viewDirection[2], 1])
    tempEnd = np.dot(tempEnd, self.Minv)
    tempEye = np.dot(tempEye, self.Minv)
    tempDirection = np.dot(tempDirection, self.Minv)
    tempDirection = tempEnd - tempEye
    ray.eyePoint = np.array([tempEye[0], tempEye[1], tempEye[2]])
    ray.viewDirection = np.array([tempDirection[0], tempDirection[1], tempDirection[2]])

    for node in self.children:

    	tempSect = node.intersect(ray)

    	if (tempSect.t < tmin):

    		isect = tempSect
    		tmin = isect.t

    tempn = np.array([isect.n[0], isect.n[1], isect.n[2], 1])
    tempp = np.array([isect.p[0], isect.p[1], isect.p[2], 1])

    tempn = np.dot(self.M, tempn)
    tempp = np.dot(self.M, tempp)

    isect.n = GT.normalize(np.array([tempn[0], tempn[1], tempn[2]]))
    isect.p = np.array([tempp[0], tempp[1], tempp[2]])

    # ===== END SOLUTION HERE =====